40 Gbit/s directly modulated lasers become reality

Optical Telecommunication requires semiconductor injection lasers with emission wavelengths around 1.3 µm and 1.55 µm. Here, good semiconductor lasers can be directly modulated in their intensity up to data rates of 10 Gbit/s, which is the most cost-efficient solution for generation of optical data signals. Up until recently, data rates beyond this level have necessitated use of an additional external modulator. Now, InGaAsP-semiconductor lasers can be directly modulated at 40 Gbit/s with the requisite performance for optical communication networks.